Saving Your Bacon with Linux RCS

Luke Hebert

- 2 minutes read - 238 words

RCS (Revision Control System) is a lightweight, file-based version control tool that has been part of Unix and Linux systems for decades. It is especially useful for tracking changes to configuration files, scripts, and documents without the overhead of a full VCS like Git. Below is a compact cheat sheet for the most common RCS commands.

Core Commands

CommandPurpose
rcsInitialize a new RCS repository for a file (creates the .v file).
ciCheck in a file, storing a new revision in the repository.
coCheck out a file from the repository into the working directory.
rlogList the commit log, showing revision numbers, authors, dates, and log messages.

Typical Workflow

  1. Initialize the repository for a file:

    rcs myfile.txt

    This creates RCS/myfile.txt,v to hold revision history.

  2. Check in the initial version:

    ci -m "Initial import" myfile.txt

  3. Edit the file, then check in the updated version:

    ci -m "Updated timeout values" myfile.txt

  4. Check out a specific revision when you need to inspect or restore it:

    co -r 1.2 myfile.txt

  5. Review the full history:

    rlog myfile.txt

Tips

  • Use ci -u to check in and immediately unlock the file for further editing.
  • Use co -l to lock a file for exclusive editing, preventing others from checking in changes simultaneously.
  • RCS stores all revisions in a single .v file under an RCS/ directory, making it easy to back up or migrate.

References